How Boat Lift Lab Compiles Its Data
Quick answer
Our cost ranges, boat weights and service-life tables are compiled estimates built from manufacturer documentation, published specifications, installer pricing and engineering fundamentals. They are planning ranges with stated assumptions, reviewed at least yearly, not quotes or measurements of your equipment.
On this page
Several pages on Boat Lift Lab rely on numbers: what lifts cost installed, what boats weigh with a real load, how long cables and motors last in different water, and the formulas behind our calculators. This page explains where those numbers come from, what they are good for, and where they stop being reliable.
Principles
- Ranges, not points. Boat lift costs and service lives vary too much by site and use for a single number to be honest. We publish ranges and name the factors that move a result within them.
- Stated assumptions. Every table says what it includes and excludes. If an assumption does not fit your situation, you can adjust for it.
- One set of numbers. Guides, reference tables and calculators share the same core figures, so a cost in a guide matches the estimator and a weight in the database matches the capacity calculator.
- No invented precision. We do not publish surveys we did not run or statistics we cannot trace. Where a figure is our estimate, we say so.
Installed cost ranges
The cost index and the cost estimator describe typical installed costs in US dollars for the current year. They are compiled from:
- publicly listed retail prices for lifts and lift packages by type and capacity class;
- published dealer and contractor pricing for installation, pilings, electrical work and canopies where available;
- the cost structure of each lift type (frame material, drive system, structure needed) to fill gaps between published points.
"Installed" means the lift plus a standard installation: delivery, assembly, setting the lift and connecting to power that is already at the lift. Pilings, new electrical circuits, salt water upgrades, canopies, permits and regional labor differences are handled as separate adjustments so readers can see what drives the total. Ranges are reviewed at least once a year, and the year is shown in the index title.
Limits: real quotes depend on access (barge work costs more than land access), local labor rates, demand after storms, soil and water conditions, and the specific product. The ranges are for budgeting and for sanity-checking quotes, not for replacing them.
Boat weights
The boat weight database gives typical dry weight ranges by boat category and length, then adds the loads that a lift actually carries. Dry weight ranges are compiled from builders' published specifications across many models in each category. Loaded weights use fixed conversion factors:
| Item | Value used |
|---|---|
| Gasoline | about 6.1 lb per US gallon |
| Diesel | about 7.1 lb per US gallon |
| Fresh water and ballast water | about 8.3 lb per US gallon (62.4 lb per cubic foot) |
| Sea water (buoyancy) | about 64 lb per cubic foot |
| Lead-acid battery, group 24 to 31 | about 50 to 75 lb (calculator uses 65 lb) |
| Gear allowance | typically 300 to 800 lb |
Limits: engines, options and builder conventions vary widely, and some spec sheets exclude the engine. Your boat's own spec sheet, or a weigh ticket, always beats a category range.
Component service life
The component lifespan tables give expected service life ranges for cables, sheaves, motors, gearboxes, bunks, hydraulic parts and structure in fresh, brackish and salt water. They combine manufacturer maintenance and replacement guidance, wire rope inspection and retirement criteria, corrosion behavior of the materials involved, and the typical replacement intervals that dealers and service companies publish.
Limits: service life depends heavily on use, maintenance, water chemistry, stray current and storms. The tables are guidance for planning inspections and budgets. Replacement should always be driven by inspection: a cable with broken wires is due no matter how young it is.
Calculator formulas
Each calculator page documents its formula and shows its working in the result, so any number can be checked by hand:
- Capacity calculator: loaded weight = dry weight + engine (if not included) + fuel + water + ballast + batteries + gear; recommended rating = loaded weight x (1 + margin).
- Water depth checker: low water depth must exceed draft + lowered bunk height + clearance; lowered bunk height + travel must exceed high water depth + wave allowance.
- Solar sizing: amp-hours per trip from motor current and run time, averaged per day with a standby draw, then battery and panel sized from reserve days, depth of discharge, sun hours and a 0.75 system efficiency.
- Cost estimator: interpolates the cost index by capacity, then adds itemized options and a regional factor.
- Lift finder: a transparent scoring of lift types against site conditions, with the reasons shown.
Review and updates
Data pages show their last update date. Cost ranges are reviewed at least once a year and after major market events (for example, regional demand spikes after hurricanes). Other tables are reviewed when new information changes them. Corrections follow our corrections policy.
Using our data
You are welcome to cite our tables with a link to the page. If you are a manufacturer, dealer or installer and have documentation that would improve a range, please contact us; we evaluate submissions against our sources and do not accept payment for changes.
Sources and further reading
- Manufacturer installation manuals, owner's manuals and published specifications for boat lifts, motors and boats.
- NOAA Tides and Currents for tidal datums used in depth guidance: tidesandcurrents.noaa.gov.
- Wire rope industry inspection and retirement guidance (Wire Rope Technical Board).
- Boat Lift Lab editorial standards.